Concrete-form joist hanger



May 6, 1930. A. M' DONALD 1,757,321

CONCRETE FORM JOIST HANGER Filed July 9, 192a I N VEN TOR.

ATTORNEYJ l Patented May 6, 1930 srares ALAN MACDONALD, OF SANFRANCISCO, CALIFORNIA CONCRETE-FORM J'OIST HANGER Application filed July9, 1928. Serial No. 291,185.

My invention relates, in general, to concrete-form construction, and, inparticular, to a novel joist-hanger for use in forms adapted forbuilding flat concrete slabs.

Such forms comprise a platform of wood, on top of which the concrete ispoured; joists, upon which the planking of said platform is laid; andposts, which support the joists. After the concrete is set, the posts,planking and joists are removed.

Both in the building of the form, and in its removal there are certainconsiderations, which open the way to improvement over common practise;for example, ease of erection, stability in use, facility indismemberment, and, mostimportant, the avoidance of injury tending topreclude the practically indefinite reuse of the lumber.

It is in these particulars that my invention hasits object; and to thisend it consists in the novel joist hanger which I shall hereinafterfully describe by reference to the accompanying drawings, in which isillustrated the preferred form of the device, it being understood thatchanges may be made without departing from the spirit of the inventionas defined by the claims hereunto appended.

In the drawings Fig. 1 is a plan of the form.

Fig. 2 is a section on the line 22 of Fig. 1 including the concreteslab.

1 is a post. 2 is a joist extending between posts. 3 is the planking ofthe platform upon which the concrete 4 shown in Fig. 2 is poured.

The planking 3 is supported upon the joists, and the joists aresupported by the posts. 5 is the bracket member of the joisthanger. Itis a metal plate bent in what may be termed a right-angle Z shape, andformed with an angular or diagonal foot extension.

Specifically, it comprises a horizontal head section a, a vertical bodysection b, a horizontal foot section 0, a downwardly and backwardlydiagonal foot extension section d and a vertical extremity section 6.The foot section 0 is slotted at 7, and the foot extension section d isslotted at g.

The other member of the hanger is a wedge 6 seated in the slottedsections 0 and d.

The hanger is fitted to the post 1 by nailing its head section a on topof the post. Its body section 6 lies snug against the side of the post.Its foot section 0 is perpendicular In order to better understand theadvan- 6 tages of my hanger, it will be well to briefly point out commonpractise in form-construction of this type. Such practice consists innailing upon the side of the post a small cleat of wood. Upon this cleatthe joist rests, a few nails being usually driven through the joist intothe post to hold it in place until the posts are braced. Nailing thecleats to the sides of the posts damages the posts so that they cannotbe used again to any great extent.

Bythe use of my hanger, all nailing into the post is eliminated, withthe exception of. the original nailing of the hanger to the post, thehanger remaining on the post until it used up. With my hanger, thevertical load of the joist is braced by the diagonal foot extension (Zattached to the post. By the use of the wedge member 6 the joist ispressed snugly against the vertical body section 7) of the hanger,thereby eliminating all preliminary nailing. After the concrete is set,the wedge 6 can be easilyknocked out from the bottom, and the joistremoved horizontally, allowing all the planking to fall with theexception of the one plank over the post. The fact that this one plankremains is of great advantage. It enables the contractor to strip 90% ofthe concrete slab, allowing the air to get to it, but still leaving oneprop in the center of each panel. It has been customary to strip aconcrete floor, taking down all the shores and posts and then return andre-erect the posts until the concrete is thirty days old. Suchre-erection is eliminated by my device. The aim of building form workfor pouring concrete, is to use as little lumber as possible, drive asfew nails as possible, and so erect the work that it can be taken downwith the greatest ease and with the IOU least damage to the lumber, sothat it can be used again.

That this aim is realized by my invention may be seen from the followingadvantages: to wit, ease of erection, due to the fact that the wedgeholds the joists in place without nailing; reuse of all shores, since nonails are driven into tlfi em, avoiding sfplitti 'ig and other injury;ability to strip practically the entire floor and leave oneslab-supporting shore, without re-shorin'gt'saving in lumber and labor,this hanger remalning with the post and can be taken to another job andused again and, finally, greater strength, avoiding splitting and comingoff of cleats, sometimes dropping a, large area of wet concrete.

I claim I 1. In concrete-torms of the type-described, and in combinationwith the posts, joists and planking thereof, a hanger comprising abracket member of approximately Z shape, hung from and secured to thepost top by its head section, with its body section bearmg against theside of the post, and-its foot section supporting thejoist; and a wedgemember fitted to said foot section, adapted to tighten thejoist againstthe body section of the bracket member.

2. In concrete-formsof thetype described, and in combination with theposts, joists and planking thereof, a hanger comprising an approximatelyZ-shaped bracket member hung from and secured to the post top by itshead section,vwith its body section bearv in-g1 against the side of thepost and its foot section supporting the joist, said foot section being;formed with an underlyingextensionsecured to the post side; and a. wedgemember sea-ted in'said foot sectionand its n-nderlying extension,adapted to tighten the joist against the body section of the bracketmember. r

In testimony whereof I have signed my name'to-t'his specification. ALANMAGDONALD.

